Experimental Measurement System

[rgsparber]

I wanted an excuse to learn how to program an Arduino (computer system on a chip) so decided to see if I could improve the performance of a $10 Harbor Freight caliper. The results are shown in these two videos. The first shows the basic functionality of automatic hold, automatic minimum detection, and automatic maximum detection. It also shows half of the measured value at all times. This can be handy if you are working on a lathe and you measure diameter yet the cutter in-feed is marked for radius.

The second video shows how gage blocks can be used to build an error correction table that improves the accuracy of the caliper.

One possible future feature that would be very easy to add would be a go/no-go test. The display screen would show "below", "OK", or "above" and not bother the minimally trained user with an actual number.

I would be interested is hearing other suggestions for new features.

Thanks,

Rick

The basic system:

Improved accuracy using gage blocks:

For full details, please see

http://rick.sparber.org/CBOO.pdf

[kbalch]

Hi Rick,

Looks great, as always. Do you have a page on your site for this project, or just the YouTube videos? For the sake of consistency, I'd prefer to have all of your projects linked back to your own site.

If not, no problem. I can always link to this forum thread.

Ken

[rgsparber]

Ken,

I will be writing this up soon but wanted to test the waters with the videos first. I was hoping to gather a few suggestions for new features before finishing the programming and starting the docs.

Rick

[kbalch]

Rick,

Got it. Just post in this thread again when you're ready and I'll add it to the database.

For a work-in-progress, it looks quite usable. I'm looking forward to seeing the finished version.

Ken

[rgsparber]

Hi Rick,

Looks great, as always. Do you have a page on your site for this project, or just the YouTube videos? For the sake of consistency, I'd prefer to have all of your projects linked back to your own site.

If not, no problem. I can always link to this forum thread.

Ken

Here you are:

http://rick.sparber.org/CBOO.pdf

[kbalch]

Thanks Rick! I've added your Experimental Measurement System to our Measuring and Marking category, as well as to your builder page: Rick Sparber's Homemade Tools. Your receipt:

Experimental Measurement System by Rick Sparber

tags: caliper, Arduino, software

[rdhem2]

Sorry but I am confused. You calibrate the caliper then measure a .060" block. Display shows .059".

What are we to think?

Caliper is not accurate.

Block is actually .059".

Sorry if I am thick between the ears.

[Workshopshed]

I am following this with interest. I've been working on a rotary sensor and calibration is also a challenge.

[rgsparber]

Sorry but I am confused. You calibrate the caliper then measure a .060" block. Display shows .059".

What are we to think?

Caliper is not accurate.

Block is actually .059".

Sorry if I am thick between the ears.

The block is accurate at .0600 and the caliper is reading a thou low. The computer corrects the error and puts the result on its own display as .0600. Could you be looking at the wrong display?

Rick

[kbalch]

This thread has been moved to the Must Read subforum. Congrats (and thanks) to Rick for making such a valuable contribution!